The technical problem to be solved is the connection of a rotating part of an apparatus for carrying out chemical processes, where toxic and strong corrosive gases are involved, with a fixed part, consisting for instance of a feeding line for said gases or an exhaust line.
Of course the inside of the rotating part has to be strictly isolated from the environment and the required pressure to be maintained is a function of the process.
There are to be avoided both infiltration from the outside of materials such as gas vapor or dust, as they might pollute the process materials contained in the rotating part, and leakage of the materials which are present inside and which might be particularly toxic and corrosive. Of course all the joint parts must be made of an inert material to avoid their corrosion, and to prevent the joint.